Somewhere recently I ran across something about a tool that strips out junk from Microsoft Office generated HTML (all that 'mso...' stuff). Come to think of it, it was HTML Tidy, which comes as an integral part of HTML Kit, a freely downloadable tool.
If you have no intention of ever converting these files (or the output of your CGI-based perl code) BACK to Excel, it might be a viable option to download the command-line version of HTML Tidy and run it from your script before html2cgi.pl.
dmmYou can give a man a fish and feed him for a day ...
Or, you can teach him to fish and feed him for a lifetime